The present invention relates to containers for pourable viscous fluids such as motor oil and is more particularly directed to a form of closure or seal for the pouring spout of such containers.
Automotive motor oil is commonly sold in individual bottle-like containers formed of a flexible plastic material. Oil is added to the engine by pouring it directly from the container typically one quart at a time into the engine's oil fill tube. It is common to spill a bit of oil on the engine as the container is tipped to bring the pouring spout to the oil fill tube. The spilled oil is unsightly, can leave a messy residue on the engine, and can burn off of hot engine surfaces giving off an undesirable odor as it burns.
A common way of dealing with the spillage problem is to use a wide-mouth funnel to catch the initial spurt of oil as the container is tipped. Another approach especially adapted to the flexible plastic bottle-like container is to provide a closure over the pouring spout of the container that initially supports the weight of the oil as the container is tilted to bring its pouring spout into position over the oil fill tube, but that ruptures when the container is squeezed to let the oil pour out. Such an approach is taken for example in the following US patents: U.S. Pat. No. 4,696,328 of Rhodes, Jr.; U.S. Pat. No. 4,938,390 of Markva, U.S. Pat. No. 5,353,968 of Good, Jr., and U.S. Pat. No. 6,457,613 of Patterson. This type of prior-art approach may be subject to one or more of the following deficiencies. The ruptured closure may restrict the flow of oil to substantially less than that allowed by the full size of the dispensing opening. The pressure required to initiate the rupture of the closure may be sufficiently great as to cause the oil to spurt uncontrollably as the closure is ruptured or may be sufficiently little as to allow premature rupture of the closure for example while grasping the container to remove the cap. Once ruptured, the closure may cause the flow to be uneven and irregular. Pieces of the closure material may dislodge and be carried into the engine along with the oil.